Mechanical fasteners comprising a female fastening element with retaining filaments and a male fastening element (hook fastener) with hooks for releasably engaging the filaments are commonly used, notably on hygiene products, for example disposable wearable articles, and especially disposable wearable absorbent articles such as diapers.
Because they are economical, provide high softness, and allow keeping continuity with the remaining disposable garment which, usually, is made itself of nonwoven material, nonwoven materials have progressively replaced woven or knitted loop fastener materials for the female fastening element of such mechanical fasteners, especially in the hygiene field.
However, commercially available hook fasteners commonly used with woven or knitted loop fastener materials have proved to be inappropriate for nonwoven materials.
Some of the known hook fasteners provide little engagement with the female counterpart of nonwoven material, because their hooks have large-sized heads unable to properly penetrate the mass of interlaced filaments. Such hook fasteners lead with use to inopportune opening of the mechanical fastener, also known as “pop off”.
Other hook fasteners provide sufficient engagement, but the strength which has to be applied by the customer for opening the mechanical fastener is too high, leading to a breaking of the filaments, also known as “fuzzing”. Fuzzing has a negative visual impact and may well make the mechanical fastener unusable after repetitive closing and reopening thereof.
Attempts to provide new types of hook fasteners allowing better cooperation notably with nonwoven materials have been made in U.S. Pat. No. 4,894,060 and US Patent Publication No. 2004/0068848.
U.S. Pat. No. 4,894,060 discloses a hook fastener having hooks with small dimensions, allowing easy penetration into the counterpart. However, the hooks do not allow a good retention of the filaments and individually have little holding power.
US Patent Pub No. 2004/0068848 discloses a process for producing hook fasteners having hook heads with little thickness in transverse direction, adapted to cooperate with nonwoven materials. These fasteners, however, do not easily engage with the retaining filaments of the counterpart and cannot be safely removed from their counterpart without breaking the retaining filaments.
In view of the foregoing, there is still a need for providing an improved hook fastener engageable with a female counterpart having filaments, particularly a nonwoven counterpart.